[1 of 1] Processing number-unknown
  [1 of 2] Compiling NumberUnknown[sig] ( number-unknown/NumberUnknown.hsig, nothing )
  [2 of 2] Compiling NumberStuff      ( number-unknown/NumberStuff.hs, nothing )

RepPolyBackpack1.bkp:17:5: error: [GHC-55287]
    The second pattern in the equation for ‘funcA’
    does not have a fixed runtime representation.
    Its type is:
      Number l :: TYPE (Rep l)